Recently, the BLU-RAY disc format has been developed as an attachable disc recordable medium format. The BLU-RAY disc format uses a disc recording medium whose diameter is 12 cm, cover layer of 0.1 mm, and blue-violet laser whose wave length is 405 nm. Its capacity is about 25 GB. By using this format, it is possible to record a high definition television signal for more than 2 hours without deteriorating the image.
It is assumed that the source of AV (Audio/Video) signal recorded on this recordable medium can be an analog video signal and a digital television signal. The BLU-RAY format to record these AV signals has been already developed.
On the other hand, a read only medium format, which is a format to define a previously recorded movie or music on a media, is still under development. Although DVD (digital versatile disc) is widely known and popular as a disc to record movies and music, the BLU-RAY disc is superior to DVD in that it is possible to record high definition television signals of more than two hours by its high capacity and high transfer rate.
A “menu” is often recorded with content to control execution of various programs relating to content when selling package medium recorded contents, such as a movie. For example, the menu is displayed by pressing a remote control commander button, and a user selects the menu item using an arrow key. Then play-back device then executes a predetermined process (or operation) corresponding to the menu item selected on the remote commander.
A BLU-RAY read only disc player will display a menu when the user inputs a user operation while playing contents. That is to say, while playing contents, the menu is displayed on top of the playing contents (e.g., movie, video, or image) by the user pressing a predetermined button on the remote commander or play-back unit. A technique to keep playing contents while displaying a menu is disclosed in patent documents JP2005-222683.
As recognized by the present inventors, this reproducing apparatus (or play-back unit) controls the display of the menu and the contents using a same time axis. Therefore, for example, when the user makes the movie temporally stop (i.e., pause), the menu that is displayed on top of the content is also paused and so user operations (menu selections) are neither accepted nor executed.
By way of example, the present inventors recognized the situation where a user can change a spoken language (eg. Japanese and English) and a subtitle (eg. Japanese and English) by using the displayed menu while playing the contents. For example, when a user try to change a spoken language and a subtitle while the content is being played, the user is forced to stop watching the content in order to change the language and subtitle.
On the other hand, after displaying the menu, the user cannot change the spoken language and subtitle because the displayed menu also stops as described above. Therefore after the user changes the spoken language and subtitle while the content is being played, the user needs to reverse the video so as to watch the portion of the content that he was previously watching prior to changing the language and subtitle settings.